# In a Flash

An inflated balloon has potential energy in the stretched rubber.

## Potential energy

Potential energy is the energy stored within an object, due to the object's position, arrangement or state.

Potential energy is one of the two main forms of energy, along with kinetic energy.

# Burning Questions

Kinetic energy used to compress a spring is stored as potential energy until released.

## What is potential energy?

Potential energy is energy that is stored – or conserved - in an object or substance. This stored energy is based on the position, arrangement or state of the object or substance.

You can think of it as energy that has the 'potential' to do work. When the position, arrangement or state of the object changes, the stored energy will be released.

For example, it requires energy to compress a spring – but what happens to that energy once the spring has been compressed? After all, we know that energy cannot be created or destroyed, it can only be converted from one form to another.

Well, in the case of our spring, the kinetic energy used to compress the spring has been converted to potential energy. When we release the spring, the stored potential energy will be converted back into kinetic energy.

## What are the different types of potential energy?

There are two main types of potential energy:

• Gravitational potential energy
• Elastic potential energy

Higher objects (with further to fall) have greater potential energy.

The heaviest of 2 objects at the same height has the greatest gravitational potential energy.

## Gravitational potential energy

Gravitational potential energy is energy in an object that is held in a vertical position, due to the force of gravity working to pull it down.

The amount of gravitational potential energy an object has depends on its height and mass. The heavier the object and the higher it is above the ground, the more gravitational potential energy it holds.

Gravitational potential energy increases as weight and height increases.

Potential energy is energy that is stored in an object or substance.

Gravitational potential energy is energy in an object that is held in a vertical position.

Elastic potential energy is energy stored in objects that can be stretched or compressed.

## Elastic potential energy

Elastic potential energy is energy stored in objects that can be stretched or compressed, such as trampolines, rubber bands and bungee cords.

The more an object can stretch, the more elastic potential energy it has.

## What are some examples of potential energy?

Examples of potential energy include:

A rock sitting on the edge of a cliff. If the rock falls, the potential energy will be converted to kinetic energy, as the rock will be moving.

A stretched elastic string in a longbow. When the elastic string is released, it will cause the arrow to shoot forward.

A sparkler. The chemical potential energy in a sparkler will be released when the top of the stick is lit.

The food we eat. Food contains chemical potential energy – as our bodies digest it, the stored energy is converted into energy for us to move and grow.

# What Do You Mean?

A swimmer's gravitational potential energy is converted to kinetic energy on diving.

Potential energy is energy that is stored in an object or substance.

Gravitational potential energy is energy in an object that is held in a vertical position.

Elastic potential energy is energy stored in objects that can be stretched or compressed.

# Cool Facts

The term 'potential energy' was first used by a Scottish engineer called William Rankine during the 19th century.

# Cool Facts

The concept of potential energy dates all the way back to the ancient Greek philosopher, Aristotle.

# Speedy Summary

A spring stores elastic potential energy because it can be stretched or compressed.

Potential energy is energy that is stored in an object or substance. The two main types of potential energy are gravitational potential energy and elastic potential energy.

# Teacher's Toolkit

Take this to the classroom!